Any Seattle-Tacoma area hypermilers out there? Looking for advice

I'm a mild hypermiler, but don't do that route frequently enough to say much about it.

My best advice:
(1) go to CleanMPG.com and read the stickies about Beating the EPA and about Prius specific methods (similar threads here, but I haven't kept a handy list);
(2) get off I-5, take a slower route;
(3) MPG must fall when climbing, it is a matter of basic physics, so don't fret about one-way trips with elevation gain;
(4) pay more attention the round trips, and do your best to hypermile the downhills to recover the fuel lost on the uphills. The downhill segments are where it is easiest to mess up the round trip MPG. The apparently high MPG makes it easy to become complacent, when one really should be getting even higher numbers due to the downhill gravity assist.

What was your speed? I regard that stretch as one of the free-fire zones (when it isn't backed up), so depending on how fast you drive it, you might already be getting what Prius can achieve.

 

Can't help you much w/hypermiling tips or that route, but perhaps your mileage drop is due to AC use since we finally have some hot weather, necessitating AC use.

I too would like to meet some Puget Sound area hypermilers for some demos and tips.

My current mileage is on my 06 is now poor since I have VERY short drives to/from work now (including a fair amount of uphill to work). There's little I can do other than block the grille when it's cold + being careful about heater use w/cold ICE. EBH is not an option for me since I'm an apartment.

When I lived in CA, only a tiny part of my route was conducive for pulse & glide and highway speeds were higher there (limit of 65 mph, meaning I'd do between 67-75 mph on the highway portion of my commute), which kept my mileage <50 mpg unless I stayed <70 mph for an entire tank.

 

Going up the Southcenter hill southbound drops my mileage anywhere from 0.3 to 0.5 mpg - but I make it up going down from Enchanted Parkway to Fife. Same going the other direction... so it tends to even out.

 

Another question: what is your one-way distance and elevation change? This will help me estimate how much MPG difference to expect in the two directions, if all else (e.g. temperature and wind) is equal.

My digital topo shows the Southcenter Hill to be about 400 feet. That should require about as much extra gas as two miles of flat road.

 

I thought the whole idea of using I-5 was to go slow

 

I drive from Tacoma to Seattle and back almost everday, often go over 70 mph, and use AC sometimes. My Prius is new. My first tank got 54 mpg calculated after subtracting the initial 22 miles from time at the dealer (the computer read around 52 mpg). My computer readout on the second tank is around 58.5 mpg with 300 miles into the tank.

I suggest inflating your tires to at least 40 psi. I have to think that I-5 (zero stoplights) will give much better MPG than 99 which has what 40-50 stoplights? Also try to time your I-5 trip north bound from Tacoma to Seattle to occur after 8am, and south bound from Seattle to Tacoma after 6pm. Basically try to avoid grid lock hours on I-5.

 

Heck, I'd say you're doing fine. I drive from Port Orchard to Kent frequently, a 100 mile rndtrip, averaging about 65, and I usually get 51 mpg (08 Touring, stock). I drive in off-peak hours, so I am able to use my cruise control for much of the trip. Maintain as steady a speed as you can, feather your accelerator delicately to keep the ICE off on level stretches, and as Ananda suggested, inflate your tires to 40 psi.